scholarly journals The effect of acquisition resolution on orientation decoding from V1: comparison of 3T and 7T

2018 ◽  
Author(s):  
Ayan Sengupta ◽  
Oliver Speck ◽  
Renat Yakupov ◽  
Martin Kanowski ◽  
Claus Tempelmann ◽  
...  
Keyword(s):  
Signal To Noise Ratio ◽  
3 Tesla ◽  
7 Tesla ◽  
Visual Orientation ◽  
Bold Signal ◽  
Signal Change ◽  
Spread Function ◽  
Voxel Selection ◽  
Spatial Acquisition ◽  
Stimulation Paradigm

AbstractPreviously published results indicate that the accuracy of decoding visual orientation from 7 Tesla fMRI data of V1 peaks at spatial acquisition resolutions that are routinely accessible with more conventional 3 Tesla scanners. This study directly compares the decoding performance between a 3 Tesla and a 7 Tesla dataset that were acquired using the same stimulation paradigm by applying an identical analysis procedure. The results indicate that decoding models built on 3 Tesla data are comparatively impaired. Moreover, we found no evidence for a strong coupling of BOLD signal change magnitude or temporal signal to noise ratio (tSNR) with decoding performance. Direct enhancement of tSNR via multiband fMRI acquisition at the same resolution did not translate into improved decoding performance. Additional voxel selection can boost 3 Tesla decoding performance to the 7 Tesla level only at a 3 mm acquisition resolution. In both datasets the BOLD signal available for orientation decoding is spatially broadband, but, consistent with the size of the BOLD point-spread-function, decoding models at 3 Tesla utilize spatially coarser image components.

1,5 Tesla versus 3 Tesla versus 7 Tesla MRT des Abdomen - eine Feldstärkenvergleichsstudie

2013 ◽  
Vol 185 (S 01) ◽  
Author(s):  
L Umutlu ◽  
S Maderwald ◽  
A Fischer ◽  
M Forsting ◽  
M Ladd ◽  
...  
Keyword(s):  
3 Tesla ◽  
7 Tesla

scholarly journals Breast MRI at 7 Tesla with a bilateral coil and T1-weighted acquisition with robust fat suppression: image evaluation and comparison with 3 Tesla

2013 ◽  
Vol 23 (11) ◽  
pp. 2969-2978 ◽  
Author(s):  
Ryan Brown ◽  
Pippa Storey ◽  
Christian Geppert ◽  
KellyAnne McGorty ◽  
Ana Paula Klautau Leite ◽  
...  
Keyword(s):  
Breast Mri ◽  
Fat Suppression ◽  
3 Tesla ◽  
7 Tesla ◽  
Image Evaluation

scholarly journals 2½-minute 3D 7T 31P-MRSI of the human heart using concentric rings (CRT)

2021 ◽  
Author(s):  
William T Clarke ◽  
Lukas Hingerl ◽  
Bernhard Strasser ◽  
Wolfgang Bogner ◽  
Ladislav Valkovic ◽  
...  
Keyword(s):  
Signal To Noise Ratio ◽  
Variable Number ◽  
Low Rank ◽  
Acquisition Time ◽  
Temporal Data ◽  
Scan Time ◽  
Spread Function ◽  
3D Acquisition ◽  
Spatio Temporal ◽  
31P Mrsi

A 3D density-weighted concentric ring trajectory (CRT) MRSI sequence is implemented for cardiac 31P-MRS at 7T. The point-by-point k-space sampling of traditional phase-encoded CSI sequences severely restricts the minimum scan time at higher spatial resolutions. Our proposed CRT sequence implements a stack of concentric rings trajectory, with a variable number of rings and planes spaced to optimise the density of k-space weighting. This creates flexibility in acquisition time, allowing acquisitions substantially faster than traditional phase-encoded CSI sequences, while retaining high SNR. We first characterise the signal-to-noise ratio and point spread function of the CRT sequence in phantoms. We then evaluate it at five different acquisition times and spatial resolutions in the hearts of five healthy participants at 7T. These different sequence durations are compared with existing published 3D acquisition-weighted CSI sequences with matched acquisition times and spatial resolutions. To minimise the effect of noise on the short acquisitions, low-rank denoising of the spatio-temporal data was also performed after acquisition. The proposed sequence measures 3D localised PCr/ATP ratios of the human myocardium in 2.5 minutes, 2.6 times faster than the minimum scan time for the acquisition-weighted phase-encoded CSI. Alternatively, in the same scan time a 1.7-times smaller nominal voxel volume can be achieved. Low-rank denoising reduced the variance of measured PCr/ATP ratios by 11% across all protocols. The faster acquisitions permitted by 7T CRT 31P-MRSI could make cardiac stress protocols or creatine kinase rate measurements (which involve repeated scans) more tolerable for patients without sacrificing spatial resolution.

scholarly journals Labeled Multi-Bernoulli Filter Joint Detection and Tracking of Radar Targets

2019 ◽  
Vol 9 (19) ◽  
pp. 4187 ◽  
Author(s):  
Rang Liu ◽  
Hongqi Fan ◽  
Huaitie Xiao
Keyword(s):  
Likelihood Function ◽  
Signal To Noise Ratio ◽  
Mutual Interference ◽  
Joint Detection ◽  
Detection And Tracking ◽  
Point Spread ◽  
Spread Function ◽  
Bernoulli Filter ◽  
Effectiveness And Efficiency ◽  
Radar Targets

A labeled multi-Bernoulli (LMB) filter is presented to jointly detect and track radar targets. A relevant LMB filter is recently proposed by Rathnayake which assumes that the measurements of different targets do not overlap, leading to the favorable separable likelihood assumption. However, new or close tracks often violate the assumption and lead to a bias in the cardinality estimate. To address this problem, a one-to-one association method between measurements and tracks is proposed. In our method, any target only corresponds to its associated measurements and different tracks have little mutual interference. In addition, an approximate method for calculating the point spread function of radar is developed to improve the computational efficiency of likelihood function. The simulation under low signal-to-noise ratio scenario with closely spaced targets have demonstrated the effectiveness and efficiency of the proposed algorithm.

scholarly journals Clinical value of (dedicated) 3 Tesla and 7 Tesla MRI for cT1 glottic carcinoma: A feasibility study

2019 ◽  
Vol 4 (1) ◽  
pp. 95-101
Author(s):  
Sylvia L. van Egmond ◽  
Bernard M.D. Vonck ◽  
Johanna J. Bluemink ◽  
Frank A. Pameijer ◽  
Jan Willem Dankbaar ◽  
...  
Keyword(s):  
Feasibility Study ◽  
3 Tesla ◽  
7 Tesla ◽  
Glottic Carcinoma ◽  
Clinical Value ◽  
7 Tesla Mri

scholarly journals MDMA (ecstasy) use is associated with reduced BOLD signal change during semantic recognition in abstinent human polydrug users: a preliminary fMRI study

2009 ◽  
Vol 24 (2) ◽  
pp. 187-201 ◽  
Author(s):  
V. Raj ◽  
HC Liang ◽  
ND Woodward ◽  
AL Bauernfeind ◽  
J. Lee ◽  
...  
Keyword(s):  
Bold Signal ◽  
Fmri Study ◽  
Signal Change

scholarly journals Spatio-temporal point-spread function of fMRI signal in human gray matter at 7 Tesla

NeuroImage ◽  
2007 ◽  
Vol 35 (2) ◽  
pp. 539-552 ◽  
Author(s):  
Amir Shmuel ◽  
Essa Yacoub ◽  
Denis Chaimow ◽  
Nikos K. Logothetis ◽  
Kamil Ugurbil
Keyword(s):  
Gray Matter ◽  
Point Spread Function ◽  
7 Tesla ◽  
Fmri Signal ◽  
Point Spread ◽  
Spread Function ◽  
Spatio Temporal

Measurement of visual sensitivity in migraine: Validation of two scales and correlation with visual cortex activation

Cephalalgia ◽  
2014 ◽  
Vol 35 (7) ◽  
pp. 585-592 ◽  
Author(s):  
Brett Cucchiara ◽  
Ritobrato Datta ◽  
Geoffrey K Aguirre ◽  
Kimberly E Idoko ◽  
John Detre
Keyword(s):  
Visual Cortex ◽  
Visual Stimulus ◽  
Visual Sensitivity ◽  
Strongly Correlated ◽  
Bold Signal ◽  
Visual Discomfort ◽  
Bold Fmri ◽  
Signal Change ◽  
And Control

Objective The objectives of this article are to compare interictal and ictal visual sensitivity between migraine and controls using two published questionnaires, and to correlate responses with a physiologic measure of visual cortex activation. Methods Migraine with (MWA, n = 51) and without (MwoA, n = 45) aura and control individuals ( n = 45) were enrolled and underwent BOLD fMRI with a visual stimulus. The visual discomfort score (VDS) assessed interictal and the migraine photophobia score (MPS) assessed ictal visual sensitivity. Result VDS was significantly higher both in MWA and MwoA vs controls (both p < 0.0001). MPS was greater in MWA vs MwoA ( p = 0.008). Ictal and interictal visual sensitivity strongly correlated in MWA ( p = 0.004) but not MwoA patients ( p = 0.12). BOLD activation in visual cortex was greater in MWA vs controls (2.7% vs 2.3%, p = 0.003) but similar between MwoA and controls. Increasing VDS was associated with greater BOLD signal change in MWA ( p = 0.03) but not MwoA ( p = 0.65) or controls ( p = 0.53). MPS did not correlate with BOLD activation in either group. Conclusion Increased interictal visual sensitivity is present both in MWA and MwoA. However, the correlation with ictal visual sensitivity and with cortical hyper-responsivity varies between MWA and MwoA, suggesting underlying differences between groups.

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